1. Field of the Invention
The invention pertains generally to the field of aircraft armaments. In greater particularity, the invention pertains to automatic, high-rate-of-fire weapons, such as Gatling type machine guns or Gatling type cannons. By way of further characterization, the invention relates to a device for protecting aircraft structure and performance from the destructive effects of the gun blast associated with the firing of these weapons.
2. Description of the Prior Art
Arming aircraft with powerful, high-performance guns is a goal of today's military aircraft designers. Yet, the high pressure muzzle blast of an operating gun poses dangers to the host aircraft. The blast can damage aircraft structure and instruments. Further, engine operational problems such as compressor stall and engine flame-out can occur if guns are operated in proximity to engine intake ducts. The engine problems relate to the muzzle blast effects on air flow and air density in the vicinity of the ducts.
Methods of eliminating these dangers have focused on directing and/or diffusing the muzzle blast. Common schemes involve attaching a diffuser directly or indirectly to the muzzle of an aircraft gun, and then placing both the gun and diffuser within a housing. The diffusers of conventional design have both gas stripper sections and gas expansion sections. The stripper sections divert the blast from the neighborhood of the muzzle. The diverted blast then expands to a low pressure in the diffuser's expansion sections. Further expansion of the blast takes place within the housing surrounding the diffuser.
One method of blast control for aircraft mounted Gatling guns incorporates a blast diffuser similar to a pre-World War One muzzle brake. This diffuser is fastened directly to the muzzle ends of the gun's barrels. Though partially effective in controlling blast, the diffuser's weight causes the Gatling gun's rotating barrels to whip. The whipping motion increases the gun's shot dispersion and decreases its accuracy. Another means of Gatling gun blast control involves mounting a stationary diffuser independent of the gun's barrels. This type diffuser requires a generally oval shape to accommodate variations in firing barrel alignment and in propellant burning rates. Unfortunately, the oval shape allows some muzzle blast to escape the stripping and directing action of the diffuser.
Further reduction of muzzle blast effect is achieved by enclosing the diffusers within housings. The housings serve as expansion chambers in which high pressure muzzle blast dissipates even further before entering the atmosphere. Besides functioning as expansion chambers, some housings direct or deflect the blast away from the aircraft, and others divert the blast back towards the gun to negate the effects of successive blasts.
Conventional blast control devices are effective in reducing the effects of aircraft gun blast; however, their physical configurations impart considerable drag on the host aircraft.